Vacuum pumps find wide usage throughout industry. For instance, vacuum pumps are used in the semiconductor industry to evacuate a process chamber. The by-products of the process taking place in the chamber can pass through the pump as the gases are evacuated from the chamber. These by-products include substances in vapour, liquid or solid phase and are often “harsh”, by which it is meant that the by-products can cause corrosion or wear of pump components exposed to the by-products.
Efforts have been made to improve vacuum pump design so that a pump can better handle by-products of harsh processes. For instance, certain pump components can be made from non-corrosive materials. Furthermore, certain vacuum pump configurations, such as the so-called “hook and claw” or Northey pumps are known to be relatively effective at handling powder entrained in the pumped gases.
A pump's ability to handle powder is an important factor when considering which type of pump should be used for certain processes known to produce powdered by-products. This is a particular problem with some semi-conductor processes where excessive amounts of silica powder are formed in a process chamber and which then pass into the pump evacuating the chamber. In the worse case scenario, the powder can cause a pump to seize and completely malfunction, resulting in potential loss of semiconductor components in the chambers and the chamber having to be taken off-line whilst a replacement pump is fitted and tested. Moreover, the effective operational lifetime of the pump is shortened by excessive exposure to powders.